FUNCTION IN PLANT LIFE 



27 



Fig. 27 gives another view of the dried-up layer, c, 

 and shows a tongue-like projection of the seed substance 



atft__ 



Fig. 27. SECTIONS OF HORSE-CHESTNUT SEED. 



[Original photo.] 



Showing projection of seed substance. 



This tongue-like projection, k, does not connect with h, nor is it so 

 pointed as in the edible chestnut ; more frequently it resembles the end 

 of a dumb-bell when cut in section transversely. The part g is assumed, 

 in this instance, to be the bottom of the seed. 



similar to that of the edible chestnut and insulated by the 

 inner membrane b in the same manner. The probable 

 purpose of this is suggested later on. 



A CONTRAST. 



I had before me, uncut, an edible and a horse-chestnut, 

 both in pod. They were free from spines, were of the 

 same colour, size, and shape, and there was nothing in 

 their outward appearance to differentiate them, except 

 that upon one the stalk still remained, to remind me that 

 it was the horse-chestnut. I cut the latter in halves, as 

 before, and photographed it. As it was in all its details 

 exactly similar to Fig. 22 there is no need to reproduce it. 

 I then proceeded to treat the 



EDIBLE CHESTNUT 



in the same way, and photographed the two separate 

 halves, shown in Figs. 28 and 29. The difference is very 



